PostScript.............................................................................................. LETTERS HIV epidemicity in context of STI declines: a telling discordance Decosas and Padian report, but do not discuss, a noteworthy disassociation in epidemic tra- jectory between human immunodeficiency virus (HIV) and sexually transmitted infec- tions (STI) in Zimbabwe. 1 They cite estimates that, between 1990 and 1999, HIV prevalence increased linearly from 9% to 25%, while STI syndrome reports declined substantially, from 963 436 cases to 727 788. The authors not only believe that observed STI declines are real, but cite increases in reported condom use by high risk people (for example, prostitute women, truck drivers, miners, and young people) as supporting evidence. What is not clear is why HIV prevalence would increase markedly coevally with increasing condom use in high risk populations and with decreasing STI incidence. Assuming synergism between STI and HIV transmission, 2 one would expect that a burgeoning and sexually mediated HIV epi- demic would be accompanied by correspond- ing increases in STI transmissions. An esti- mated increase in HIV prevalence from 9% to 25% in a decade, implying a 12% annual epidemic growth rate, is not likely to be due to differences between HIV, a chronic infection that accumulates in a reservoir, and STI, which tend not to. Does this anomaly require clarification? Recent analyses 34 suggest that a large proportion of HIV infections, especially in sub-Saharan Africa, 5 may be a consequence of unsafe medical injections. This under- suspected and scientifically underexplored transmission vector is overlooked by the authors as well (exception: “blood safety” in fig 1). Theirs is not the first report of an epidemiologically suspicious anomaly be- tween STI and HIV trends in Africa 6 and, if others’ suspicions are correct, 3–5 it is unlikely to be the last. J J Potterat Independent consultant, Colorado Springs, CO, USA S Brody Institute of Medical Psychology, University of Tübingen, Germany Correspondence to: Stuart Brody; stuartbrody@hotmail.com References 1 Decosas J, Padian N. The profile and context of the epidemics of sexually transmitted infections including HIV in Zimbabwe. Sex Transm Infect 2002;78(Suppl I):i40–6. 2 Wasserheit JN. Epidemiological synergy: interrelationships between human immunodeficiency virus infections and other sexually transmitted diseases. Sex Transm Dis 1992;19:61–77. 3 Holding R, Carlsen W. Deadly needles: epidemic’s devastating toll. San Francisco Chronicle.29 October 1998:A1ff. Internet version accessed 19 August 2002 http://sfgate.com/cgi-bin/article.cgi?file=/ chronicle/archive/1998/10/29/ MN10NED.DTL&type=special 4 Gisselquist D, Rothenberg R, Potterat J, et al. HIV infections in sub-Saharan Africa not explained by sexual or vertical transmission. Int J STD AIDS (in press). 5 Drucker E, Alcabes PG, Marx PA. The injection century: massive unsterile injections and the emergence of human pathogens. Lancet 2001;358:1989–92. 6 Lagarde L, Auvert B, Carael M, et al. Concurrent sexual partnerships and HIV prevalence in five urban communities of sub-Saharan Africa. AIDS 2001;15:877–84. Accepted for publication 28 August 2002 Vaginal infection by Enterobacter sakazakii In August 2001, a 26 year old woman seen at our outpatient clinic in Budapest complained of vulvar pruritus and vaginal discharge in the preceding 2 weeks. The only risk factor she admitted was that she had bathed in the resort lake Balaton a few times a week before the onset of symptoms, when the water was unusually warm (26–28°C). Examination re- vealed vulvovaginitis with mucous discharge at pH 5.5. A vaginal smear showed a large number of polymorphonuclear leucocytes, Gram negative rods, but no Lactobacillus. Culture on blood agar at 37°C for 48 hours resulted in yellow pigmented, bright, tough colonies. Biochemical analysis 1 verified Entero- bacter sakazakii. Standard disc diffusion technique, 2 on Mueller-Hinton agar (Becton Dickinson, Sparks, MD, USA) using commer- cial discs (Oxoid, Basingstoke, UK), revealed sensitivity to carbenicillin, netilmycin, cefazo- lin, ofloxacin, tetracycline, and gentamicin; limited sensitivity to erythromycin; and re- sistance to ampicillin, clindamycin, nalidix acid, furadantin. This pattern is common in recent isolates. 3 Empirical treatment— starting before laboratory data were available—with intravaginal Pimafucort oint- ment (1% natamycin, 0.25% neomycin, 0.5% hydrocortisone) for 7 days resulted in a com- plete recovery in 2 weeks, at which time the vagina was colonised by Streptococcus agalactiae. The following week a normal Lactobacillus flora at pH 4.2 returned. Nearly 50 E sakazakii infections resulting in meningitis, necrotising enterocolitis, and one urine infection of newborns have been docu- mented. E sakazakii have been recovered from their blood, spinal fluid, throat, trachea, stom- ach aspirates, and rectum. Newborns were premature, and fed on powdered milk for- mula, which is the known source of infection. 34 The means of its contamination is not known. For affected newborns, vaginal delivery does not seem to be a risk factor, since no colonisation of the mother’s genital tract has been reported. Less than 20 isolates have been obtained from children and adults, including eight from urine and one from genital secretion. Patients had either neo- plasm or other serious underlying conditions, but their clinical details were not available. In both newborns and adults occasional coinfec- tions with Serratia marcescens, Staphylococcus aureus, Enterococcus faecalis, or Candida albicans were reported. 35 The normal habitat, reservoir, and patho- genesis of E sakazakii are unknown. No cultivation from environmental sources (sur- face water, animals, raw cow’s milk, etc) has been successful, 3 except recently from the gut of fruit flies. 6 The rare related species E intermedium causing urinary tract infection, was found in drinking water and soil. 5 Our case strongly suggested that warm surface water was the source of infection. The unusu- ally high thermal resistance of E sakazakii 3 might contribute to its survival during the manufacture powdered milk batches. 4 It is important to remember that the stomach of newborns, especially that of premature ba- bies, lacks free acid and is less acidic than that of adults. Ingested milk preparations remain- ing neutral or slightly alkaline in their stomach ensure survival and subsequent infection in the alkaline intestine. This patho- mechanism is similar to pH increase in vaginal infections in the lack of Lactobacillus flora. The detrimental effect of E sakazakii infection is also reflected by the fact that rec- olonisation by the normal flora and a pH shift towards physiological level could be achieved only gradually in our patient. J Ongrádi National Institute of Dermato-Venereology, Budapest VIII, Mária utca 41, Hungary 1085; ongjos@hotmail.com References 1 Murray PP, Baron EJ, Pfaller MA, et al, eds. Manual of clinical microbiology. 7th ed. Washington DC: ASM Press, 1999. 2 The National Committee for Clinical Laboratory Standards. Performance standards for antimicrobial susceptibility testing: eight informational supplements. Vol 18, No 1. Wayne, PA: The Committee, 1998. 3 Lai KK. Enterobacter sakazakii infections among neonates, infants, children, and adults: case reports and a review of the literature. Medicine (Baltimore) 2001;80:113–22. 4 Van Acker J, de Smet F, Muyldermans G, et al. Outbreak of necrotizing enterocolitis associated with Enterobacter sakazakii in powdered milk formula. J Clin Microbiol 2001;39:293–7. 5 Varaldo PE, Biavasco F, Mannelli S, et al. Distribution and antibiotic susceptibility of extraintestinal clinical isolates of Klebsiella, Enterobacter and Serratia species. Eur J Clin Microbiol Infect Dis 1988;7:495–6. 6 Kuzina LV, Peloquin JJ, Vacek DC, et al. Isolation and identification of bacteria associated with adult laboratory Mexican fruit flies, Anastrepha ludens (Diptera: Tephritidae). Curr Microbiol 2001;42:290–4. If you have a burning desire to respond to a paper published in Sex Transm Inf, why not make use of our “rapid response” option? 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