Intensive Care Med (1985) 11:179- 183 Intensive Care Medicine © Springer-Verlag1985 Moxalactam in nosocomial infections with Serratia marcescens T. Mall, F. Follath, M. Salfinger, R. Ritz and H. Reber Department of Internal Medicine and Microbiological Laboratory, University Hospital, Basel, Switzerland Accepted: 11 March 1985 Abstract. Ten critically ill patients presenting with nosocomial infection caused by Serratia marcescens (SM) not responding to prior chemotherapy were treated in an open study with Moxalactam t (MOX) alone [6] or in combination with an aminoglycoside [4]. In initial disc diffusion tests, all isolates of SM were highly susceptible to MOX. Clinically, three pa- tients were cured and four improved. Three patients died: one from SM pneumonia, one from gangrenous cholecystitis and another from ARDS. Bacteriologi- cally, SM were eliminated from blood cultures in all seven patients with septicemia but were recovered post mortem from the lung of one patient. In three cases with localized infection, SM were eliminated once and persisted twice. Selection of resistant SM was observed in three patients but became clinically relevant in one case only. Resistant SM strains also showed reduced susceptibility to other cephalosporins and aminoglycosides. Emergence of enterococci oc- curred four times, in two cases with clinical conse- quences. MOX is a useful drug for the treatment of SM infections, but a definite risk of selecting multire- sistant SM strains and of enterococcal overgrowth must be kept in mind. Key words: Moxalactam - Serratia marcescens - Septicemia - Enterococci Because of acquired resistance and selection of insen- sitive strains, there is a need for new antibiotics. Initial studies on new compounds usually present in vitro susceptibility data and clinical results in patients with various infections by different microorganisms 1 Officialgeneric name in the USA; trade mark (Eli Lilly & Co) in most of Europe which very often could be treated by established anti- biotics. However, the true test of new compounds, such as the third generation cephalosporins, is the therapeutic efficacy in patients with prior ineffective treatment, infected by resistant organisms. This situation is often seen in intensive care units, although the evaluation of the therapeutic benefit may be diffi- cult because of the complexity of the underlying dis- orders. In this open therapeutic study we analyzed the results obtained with one 3rd generation cephalospo- rin, Moxalactam (MOX), in 10 critically ill patients with proven infection by Serratia marcescens (SM). Until a relatively short time ago, Serratia was not con- sidered a pathogenic organism [8]. This opinion was revised according to experience derived from immu- no-compromised and long-term intensive care pa- tients. In all patients in our series SM was responsible for severe disease. Moxalactam is a semi-synthetic third generation cephalosporin with a high activity against enterobac- teriaceae, including those with multiple resistances [14, 23]. Clinically, the drug is reported to combine high efficacy with good tolerance [11]. Occasional side-effects include hematologic complications [2] and disulfiram-like ethanol intolerance [17]. Patients and methods Ten patients of both sexes aged 20-68 years (mean 42.1 years) suffering from symptomatic infection with SM were included. Characteristics of the study popu- lation are listed in Table 1. Four patients may be re- garded as compromised hosts (receiving cytotoxic or immunosuppressive treatment), but none of them had agranulocytosis at the time of SM infection. In eight patients the infection occurred during prolonged in- tensive care treatment. All these patients were artifi- cially ventilated, four also needed hemodialysis. One